Determine in which direction and how the thickness of the permafrost changes.

When looking at the map, which depicts the permafrost of Russia, you can see that the thickness of the frozen rocks is increasing in the direction from south to north, as well as from west to east. This is due to an increase in the continentality of the climate, as well as an increase in solar radiation. The highest level of frozen rocks is located in the north-east of the country.